So as to use Stacked, I installed version 8:
> pip uninstall ipywidgets > pip install ipywidgets==8.0.0b
But upon displaying a Stacked widget, this error was issued:
Error displaying Widget
Thus I then went back to version 7:
> pip uninstall ipywidgets > pip install ipywidgets
Alas, now version 7 does not work either.
I made sure all the related processes were killed. I closed all notebooks. Then:
> pip uninstall matplotlib > pip uninstall pandas > pip uninstall ipywidgets > pip uninstall jupyterlab
pip install matplotlib pip install pandas pip install jupyterlab pip install ipywidgets
And then … the exact same problem
model not found
Alas, what is the magic incantation to fix the setup?